Workaround for Neoverse N1 erratum 1220197
Neoverse N1 erratum 1220197 is a Cat B erratum [1],
present in older revisions of the Neoverse N1 processor core.
The workaround is to set two bits in the implementation defined
CPUECTLR_EL1 system register, which disables write streaming to the L2.
[1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.pjdoc-466751330-10325/index.html
Change-Id: I9c3373f1b6d67d21ee71b2b80aec5e96826818e8
Signed-off-by: Lauren Wehrmeister <lauren.wehrmeister@arm.com>
diff --git a/docs/design/cpu-specific-build-macros.rst b/docs/design/cpu-specific-build-macros.rst
index ef24f2e..ee8da17 100644
--- a/docs/design/cpu-specific-build-macros.rst
+++ b/docs/design/cpu-specific-build-macros.rst
@@ -240,6 +240,9 @@
- ``ERRATA_N1_1207823``: This applies errata 1207823 workaround to Neoverse-N1
CPU. This needs to be enabled only for revision <= r2p0 of the CPU.
+- ``ERRATA_N1_1220197``: This applies errata 1220197 workaround to Neoverse-N1
+ CPU. This needs to be enabled only for revision <= r2p0 of the CPU.
+
- ``ERRATA_N1_1315703``: This applies errata 1315703 workaround to Neoverse-N1
CPU. This needs to be enabled only for revision <= r3p0 of the CPU.
diff --git a/include/lib/cpus/aarch64/neoverse_n1.h b/include/lib/cpus/aarch64/neoverse_n1.h
index 8925827..952ae6e 100644
--- a/include/lib/cpus/aarch64/neoverse_n1.h
+++ b/include/lib/cpus/aarch64/neoverse_n1.h
@@ -30,6 +30,8 @@
******************************************************************************/
#define NEOVERSE_N1_CPUECTLR_EL1 S3_0_C15_C1_4
+#define NEOVERSE_N1_WS_THR_L2_MASK (ULL(3) << 24)
+
/*******************************************************************************
* CPU Auxiliary Control register specific definitions.
******************************************************************************/
diff --git a/lib/cpus/aarch64/neoverse_n1.S b/lib/cpus/aarch64/neoverse_n1.S
index c9bcea8..0e7b8e8 100644
--- a/lib/cpus/aarch64/neoverse_n1.S
+++ b/lib/cpus/aarch64/neoverse_n1.S
@@ -185,6 +185,33 @@
endfunc check_errata_1207823
/* --------------------------------------------------
+ * Errata Workaround for Neoverse N1 Errata #1220197
+ * This applies to revision <=r2p0 of Neoverse N1.
+ * Inputs:
+ * x0: variant[4:7] and revision[0:3] of current cpu.
+ * Shall clobber: x0-x17
+ * --------------------------------------------------
+ */
+func errata_n1_1220197_wa
+ /* Compare x0 against revision r2p0 */
+ mov x17, x30
+ bl check_errata_1220197
+ cbz x0, 1f
+ mrs x1, NEOVERSE_N1_CPUECTLR_EL1
+ orr x1, x1, NEOVERSE_N1_WS_THR_L2_MASK
+ msr NEOVERSE_N1_CPUECTLR_EL1, x1
+ isb
+1:
+ ret x17
+endfunc errata_n1_1220197_wa
+
+func check_errata_1220197
+ /* Applies to <=r2p0 */
+ mov x1, #0x20
+ b cpu_rev_var_ls
+endfunc check_errata_1220197
+
+/* --------------------------------------------------
* Errata Workaround for Neoverse N1 Erratum 1315703.
* This applies to revision <= r3p0 of Neoverse N1.
* Inputs:
@@ -252,6 +279,11 @@
bl errata_n1_1207823_wa
#endif
+#if ERRATA_N1_1220197
+ mov x0, x18
+ bl errata_n1_1220197_wa
+#endif
+
#if ERRATA_N1_1315703
mov x0, x18
bl errata_n1_1315703_wa
@@ -318,6 +350,7 @@
report_errata ERRATA_N1_1130799, neoverse_n1, 1130799
report_errata ERRATA_N1_1165347, neoverse_n1, 1165347
report_errata ERRATA_N1_1207823, neoverse_n1, 1207823
+ report_errata ERRATA_N1_1220197, neoverse_n1, 1220197
report_errata ERRATA_N1_1315703, neoverse_n1, 1315703
report_errata ERRATA_DSU_936184, neoverse_n1, dsu_936184
diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index 78efbeb..bb53dad 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -254,6 +254,10 @@
# only to revision <= r2p0 of the Neoverse N1 cpu.
ERRATA_N1_1207823 ?=0
+# Flag to apply erratum 1220197 workaround during reset. This erratum applies
+# only to revision <= r2p0 of the Neoverse N1 cpu.
+ERRATA_N1_1220197 ?=0
+
# Flag to apply erratum 1315703 workaround during reset. This erratum applies
# to revisions before r3p1 of the Neoverse N1 cpu.
ERRATA_N1_1315703 ?=1
@@ -463,6 +467,10 @@
$(eval $(call assert_boolean,ERRATA_N1_1207823))
$(eval $(call add_define,ERRATA_N1_1207823))
+# Process ERRATA_N1_1220197 flag
+$(eval $(call assert_boolean,ERRATA_N1_1220197))
+$(eval $(call add_define,ERRATA_N1_1220197))
+
# Process ERRATA_N1_1315703 flag
$(eval $(call assert_boolean,ERRATA_N1_1315703))
$(eval $(call add_define,ERRATA_N1_1315703))